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' @uiten gratta @anni @fitta IMPROVEMBNTAIN Gemme-Mms.

GEORGE L. WITSL, Oliv PHILADELPHIA, PENNSYLVANIA. Letters .Patent No. 60,105, dated November 27, 1866.

SPECIFICATION.

TO ALL WI-IOM IT MAY CONCERN:

Be it known that I, GEORGE L. WITSIL, of Philadelphia, in the county of Philadelphia, and State of Pennsylvania, have invented a new and useful 'Improvement in Machines for Crushing Substances; and I do hereby declarethat the following is afull, clear, and exact description of the same, reference being had to the annexed drawings, making part `of this speciiication, in which- Figure 1 is a perspective view. i

Figure 2 isa vertical longitudinal section. 4

The same letters are employed in both figures in indicating identical parts. i

A is the hopperifor receiving the substance to be ground, The part A is an internallyconcave chamber through which passes the shaft, B, turned bythe winch, B this shaft passes through the boxes, C, which are set'in dovetailed cleats retaining the boxes, but permitting their free play verticallya'` 'is a'set-screw` `passing Athrough alug on the hopper, and resting against a projectingarm attached to thebox; '0.1; D is a roll'er hung upon the shaft, B, and having the spiral thread of a left-hand screw raised upon its surface. The concave face of the chamber, A,is in like manner cut info alternately raised ribs and depressions, arrangedspirallyyin like manneras with the ribs`on the roller. These ribs are lshown at E, and by the dotted lines in fig. 2. -This construction of the grinding-roller is to be distinguished from that inlwhich a-series of spirallyjnclinedgrooves or'ribs are formed on a cylinder to present oppositely inclined edges to other ribs or grooves `on the concave,

in this essential feature, that I construct my cylinder with a sin'gle helical rib running'several times around the cylinder like the thread of a screwand bringing to bear Athe power of a screw in crushing substances between the rib and the irregular surfaces of the concave. Substances intended to be ground, (such as paints, clay, quartz, drugs, coffee', &c.,) being thrown into the hopper, and falling between the roller and the sides'l`of the hopper, will'be drawn by the .screw on the roller towards the end of the boxhand being pressed against and and at the same time drawn across the concave face of the chamber, A', theywill be crushed and ground between i the ribs upon the rollerand those upon the concave. The substances when ground will be discharged through an opening'in the bottom of the chamber, A', which may be closed by the plug F. i

The casing is made tight, except at the orifice of discharge, which may be closed .by the plug F, as described. This plug is to` be used `whenever the machine is used for mixing uids; the materials placed in the mill being thoroughly incorporated by `theaction of the roller before the plug is withdrawn Vwhichretains them.4

WhatI claim as my invention, and desire to secure by Letters Patent, isi- Y The roller D, when constructed with a. single helical rib like the thread of a screw, and suspended upon l the vertically adjusted shaft, B, when used in combination with thehopper A, and spirally ribbed concave A',

said parts being respectively' constructed and the whole arranged to operate substantially in the manner 'and for the purposes set forth In testimony whereof vI have signed my name to this specification in the presence of two subscribing witnesses. 'I L GEO.,L. WITSIL., Witnesses s C. F. OLAUSEN, LAWRENCE MURPHY. 

